Epoxy compounds are well known and include many compounds of varying molecular weight and epoxy equivalent weight. To simplify the production of a large number of epoxy compounds that vary mainly in molecular weight, it is common practice to manufacture a single epoxy compound of specified molecular weight and react the epoxy compound with a compound containing phenolic hydroxyl groups in the presence of catalyst so as to obtain epoxides of phenolic hydroxy ether compounds of desired higher molecular weight. The conventional catalysts employed were inorganic bases or tertiary amines which were also effective catalysts for competing reactions of epoxides with alcoholic hydroxyl groups, homopolymerization of epoxy groups and the like. As a result, the product obtained was a mixture of polymers and resins with varying degrees of molecular weight, chain branching and end group functionality. Such a composition detracts from the performance and utility of the product. More recent catalysts (termed "fusion catalysts") with improved selectivity include phosphonium halides as disclosed in U.S. Pat. No. 3,477,990, phosphines as disclosed in U.S. Pat. No. 3,547,881, and, 3-(trihydrocarbylphosphoranylidene)-2,5-pyrrolidinediones as disclosed in U.S. Pat. No. 3,843,605. Other fusion catalysts are disclosed in U.S. Pat. No. 3,948,855 (phosphonium salt of an acid, acid ester or ester of carbon or phosphorous) and U.S. Pat. No. 3,978,027 (potassium iodide). Processes involving multiple addition of catalyst to give higher molecular weight polyepoxides with narrower molecular weight distributions are disclosed in U.S. Pat. No. 4,105,634.